Another weekend down and you are almost halfway through the paleo challenge. If you have been steady, this next week is an incredibly important week. It takes about 20-21 days to get the full effect of a change in your diet. As soon as this week is over, greens will be greener, your sleep will be remarkably better, and all of a sudden you will be magically better at CrossFit. Once the nutrition element of your health and fitness journey comes into play, all else becomes better and easier.